1. Technical Field
The present invention relates to an optical semiconductor package that is packaged by sealing an optical semiconductor element typified by a light emitting element or a light receiving element by an optical transparency sealing layer, an optical semiconductor module provided with the optical semiconductor package, and a manufacturing method thereof.
2. Related Art
Nowadays, a surface mounting device attracts attention because of a demand for downsizing and low profile of an electronic device. Even in a photoelectric sensor including optical semiconductor elements such as a light emitting element typified by an LED (Light Emitting Diode) chip and a light receiving element typified by a PD (Photo Diode) chip, various packaging structures are being studied for the purpose of surface mounting of an optical semiconductor package.
Generally, in the photoelectric sensor, there is also a demand to lengthen a detection distance or detect a finer component in addition to the downsizing and the low profile of the device. In order to meet these demands, it is necessary that light use efficiency be improved such that a sufficient amount of light can be projected or received even if the downsizing and the low profile are achieved in the optical semiconductor package included in the photoelectric sensor.
That is, it is necessary to take off the light emitted from the light emitting element from the optical semiconductor package at high takeoff efficiency in a projector included in the photoelectric sensor, and it is necessary to take in the light incident to the optical semiconductor package to the light receiving element at high take-in efficiency in an optical receiver included in the photoelectric sensor.
Therefore, for example, in the description of Japanese Unexamined Patent Publication No. 2009-141317 (Patent Document 1), a metallic reflector (a reflecting plate) is buried in the optical transparency sealing layer, by which the LED chip or the PD chip is sealed, so as to surround the LED chip or the PD chip, whereby the light is reflected by a surface of the reflector to improve the light takeoff efficiency or the light take-in efficiency.
In the description of Japanese Unexamined Patent Publication No. 2010-232275 (Patent Document 2), a portion of the surface of the optical transparency sealing layer by which the LED chip is sealed extends outward, and the extended portion acts as the reflector, whereby the light is reflected by an interface of the extended portion to improve the light takeoff efficiency.
In the description of Japanese Unexamined Patent Publication No. 2006-278675 (Patent Document 3), a spherical structure having a refractive index different from that of the optical transparency sealing layer is buried in the optical transparency sealing layer by which the LED chip is sealed, whereby the light takeoff efficiency is improved by utilizing refraction and/or diffraction of the light passing through the spherical structure.
Patent Document 1: Japanese Unexamined Patent Publication No. 2009-141317
Patent Document 2: Japanese Unexamined Patent Publication No. 2010-232275
Patent Document 3: Japanese Unexamined Patent Publication No. 2006-278675